Officially commissioned on Jan. 1, 1962, U.S. Navy SEALs saw their first combat action in Vietnam. They operated in the area of the Mekong Delta, conducting search-and-destroy, recon and rescue missions. SEAL Teams 1 and 2 lost 45 men in Vietnam.

The photo below is ST-1 aboard a SEAL Team Assault Boat (STAB) on the Bassac River, Vietnam, Nov 1967. The boat is a modified civilian Power Cat 23 with two 115 hp Mercury outboards.

The Benrus Type II Class A is one of just a very few types of dive watches issued during the Vietnam War to Navy Seals, UDT Divers, and Special Forces personnel. Its distinguishing feature is its front-loading, asymmetrical case with solid, non-removable lug bars for strap attachment. Class A is the highest military grade classification a watch can be given.

Commonly referred to as a one-piece design, the Types I/II cases are in fact a two-piece design. The case back is press fit in a manner meant to be permanent. The movement is serviced through the front of the watch case by removing the bezel and crystal. This front loading style makes necessary the use of a two-piece winding stem, considered by some to be this watch's weak link.